Production of renewable fuels and energy by steam/CO2 reforming of wastes

ABSTRACT

This invention relates to a power recovery process in waste steam/CO2 reformers in which a waste stream can be made to release energy without having to burn the waste or the syngas. This invention in some embodiments does not make use of fuel cells as a component but makes use of exothermic chemical reactors using syngas to produce heat, such as Fischer-Tropsch synthesis. It also relates to control or elimination of the emissions of greenhouse gases in the power recovery process of this invention with the goal of producing energy in the future carbonless world economy.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to U.S. ProvisionalPatent Application Ser. No. 62/613,881, filed Jan. 5, 2018, incorporatedherein by reference.

FIELD OF THE INVENTION

The invention relates to a process and system in which a waste streamcan be made to release energy without having to burn the waste or thesyngas and consume oxygen and have large carbon dioxide emissions. Insome embodiments the waste can be converted into a carbon-containing,carbon sequestering fertilizer, renewable hydrogen fuel, and products ofimportant commercial value, such as unsaturated, high-density renewablefuels and paraffin wax.

BACKGROUND OF THE INVENTION

There is a great need to destroy a wide range of waste streams generatedaround the world and at the same time to convert this carbonaceous wasteinto useful hydrogen-rich syngas to accomplish one or more of thefollowing: (1) production of renewable H₂ fuel, (2) to feed anexothermic hydrocarbon synthesis reactor, such as a Fischer-Tropsch unit(FT), to produce renewable fuels, or (3) to use a portion of this syngasto drive a fuel cell to power the plant.

This steam/CO₂-reforming chemistry used in the steam/CO₂ reformer (SR)does not involve combustion. The idealized main chemical reactions,which can be considered to be chemical reduction, occur from the RRthrough the SSR main reactor is as follows:C_(a)H_(b)O_(c) +d CO₂+(a−c−d) H₂O+HEAT→(a+d) CO+(a+0.5b−c−d)) H₂and many more reactions into the hundreds:C+2H₂→CH₄CH₄+CO₂+HEAT→2CO+2H₂C+H₂O→CO+H₂C+CO₂-→2 CO+HEATH₂+CO₂<----- >H₂O+CO. . . etc.

Although the steam-reforming chemistry is just started in the rotaryreformer, it continues to near completion as the gas temperatureincreases along its path through the system into the main steam/CO2reforming reactor where more reaction occurs with superheated steampreferably without catalysts. This reaction with superheated steam has aresidence time of less than about two seconds mainly at the elevated,nearly isothermal conditions in main reactor; in some embodiments thereis not the very brief exposure to high temperatures typical of anincinerator flame region.

The challenge and problem with fuel cells has been their extremesensitivity to various unknown chemical poisons at parts per millionlevels coming from the waste streams from harming the electrochemicalcatalysts of the high temperature fuel cells. By comparisonFlory-Huggins catalysts in Fischer-Tropsch reactors (such as supportediron and cobalt catalysts) are much less sensitive to poisons than fuelcells and are highly exothermic.CO+2H₂→1/n(—CH₂—)_(n)(I)+H₂O(I)ΔH°₂₉₈=−231.1 kJ/mol

Conversion of syngas to methanol using copper catalysts in the gas phaseor liquid-phase catalysts are exothermic and also less sensitive topoisons.CO+2H₂→CH₃OH(I)ΔH°₂₉₈=−128.2 kJ/mol

There is syngas methanation that is highly exothermic:2CO+2H₂→CH₄+CO₂ΔH°₂₉₈=−247.3 kJ/mol

So these three reactions listed above cause the FT chemistry to producemany other gases besides the hydrocarbons [1/n (—CH2—)_(n) (I)] desired.In some embodiments there is a minimization of these side reactions, oruse of them, by reusing the FT tail gas through recycling back to therotary reformer. The CO2 in Steam/CO2 reforming helps minimize this sidereaction above.

All of these highly exothermic reactors produce high-grade usefulenergy, they all can convert syngas with enough exothermicity to makelarge amounts of electricity, steam and heat. These exothermic reactorscan substitute for fuel cells. Thus, an aspect of some embodiments ofthe present invention include methods and process systems to convertwaste to energy without burning the waste but to sequester the carbon ofthe waste so carbon gases are not released.

The composition of the syngas was determined in detail according to oneembodiment of the present invention from a pilot plant where med-wastewas steam/CO₂ reformed to make syngas. The syngas composition is shownin Table 1 below.

TABLE 1 Results from Pilot Plant Gas Test By Steam/CO₂ Reforming OfSolid Waste H₂ Hydrogen 62.71 vol % CO Carbon Monoxide 18.57 CO₂ CarbonDioxide 10.67 CH₄ Methane 7.58 C₂H₆ Ethane 0.48 C₃ TO C₆ Propane throughhexane <0.01 C₆H₆ Benzene <17 ppm COS Carbonyl Sulfide 4 ppm CS₂ CarbonDisulfide 0.05 ppm H₂S Hydrogen Sulfide <5 ppm C₁₀H₈ Naphthalene 2.6 ppbC₁₀H₇CH₃ 2-Methylnaphthalene ~0.6 ppb C₁₂H₈ Acenaphthalene ~0.4 ppbC₁₂H₈O Dibenzofuran 0.36 ppb PCDF + PCDD Polychlorinated- 0.0041 ppt TEQdibenzofurans + Dioxins

What has been found experimentally was that the syngas included hydrogenand carbon monoxide. For fuel cells the key poisons, such as carbonylsulfide, hydrogen sulfide, carbon disulfide, hydrogen chloride, andpolychlorinated organics were identified. For Fischer-Tropsch, methanolsynthesis, methanation, etc., this syngas is acceptable. However, tomake the process more efficient and environmentally desirable, the sideproducts, such as CH₄ and CO₂ need to be used and not released to theatmosphere. These are also the side products of FT that are called “tailgases.” Yet other aspects of some embodiments of the present inventioninclude using these side species of CH₄ and CO₂ through recycle back tothe front end of the process, such as through a rotary reformer.

Another aspect of power recovery is to reduce the energy losses of awaste-reforming kiln. One consideration is that some kilns are operatedat a high temperature, followed by an even higher temperature steam/CO₂reformer which is then followed by the desulfurizer and high temperaturefilter—all energy-inefficient from heat losses from the process unitsthemselves and from the complex of hot process piping.

Regarding Fischer-Tropsch, one aspect according to some embodiments isto develop a process train where the Fischer-Tropsch unit could produceenough high carbon product, such as fertilizer and as high density,unsaturated paraffin wax containing little hydrogen, so that the carbonin the waste feed would be sequestered in this product, withoutsignificant carbon emissions leaving the process anywhere else. TheFischer-Tropsch train also should produce steam for asteam-turbo-generator to make electricity for the process plant.

SUMMARY OF THE INVENTION

Various embodiments of the present invention relate to a power recoveryprocess in waste steam/CO₂ reformers whereby a waste stream can releaseenergy without having to burn the waste or the syngas and consume oxygenand have large carbon dioxide emissions.

Various embodiments do not make use of fuel cells as its criticalcomponent but makes use of highly exothermic chemical reactors usingsyngas to produce large amounts of heat, such as by Fischer-Tropschreactions.

Some embodiments relate to control or elimination of the emissions ofgreenhouse gases in the power recovery process of this invention withthe goal of producing energy in the future carbonless world economy.

Further, yet other embodiments show how to eliminate the typical lightgas discharge from Fischer-Tropsch, shift converters, pressure swingadsorbers, membrane systems, etc. by recycling back to the kiln as a“recycling to extinction,” because the steam reforming chemistry breaksapart these light gases into their elemental constituents.

One aspect of some embodiments include a process train for powerrecovery with an improved duplex kiln in a recycle way that combines thefunctions of the conventional kiln, steam/CO₂ reformer, and the hightemperature filter into a single unit. The desulfurizer/getter bed canoperate at a lower temperature and can follow the duplex kiln.

Further embodiments involve using the above duplex kiln and getter bedin a process train that includes a heat exchanger/steam superheater aredisclosed that will rapidly quench-cool the syngas down from 300 to 500°C. (600 to 900° F.) temperature range of the desulfurizer to 150° C.(300° F.). The concept here is to rapidly quench the syngas so that theundesirable heavy hydrocarbon recombination reactions (i.e. “De-Novo”)that make dioxins and furans do not have time to form, since they arekinetically limited. These recombination reactions involve multi-steppolymerization &/or ring formation and are slowed as the temperaturesare lowered.

In still further embodiments the Brayton cycle turbine is used torecover energy from the high temperature gas, while cooling it forfeeding to both the Fischer-Tropsch unit to produce the high-carboncontent product for sequestering the carbon and the shift converter andpressure-swing absorber to produce hydrogen fuel.

As an alternative embodiment, a conventional indirectly fired, calciningkiln can be used where the very hot syngas exiting from the steamreformer can heat carbon dioxide gas or air to supply the indirect heatto the kiln to take over from the natural gas burners commonly used.

The Fischer-Tropsch reactor, as discussed above, is highly exothermicand produces high quality steam for operating a conventional steamturbo-generator system for powering the plant.

Various embodiments of the present invention pertain to the conversionof a waste stream by steam/CO₂ reforming to produce a syngas that isused in a Fischer-Tropsch reactor as well as its tail gas recycle backto the front end to produce energy and sequester the carbon of the wasteat the same time.

Yet other embodiments replace the Fischer-Tropsch reactor with otherhighly exothermic reactors that produce a high-carbon content productfor sequestering carbon and produce large amounts of energy, and userecycle to advantage, and also interchanging the syngas cleaning processunits around while keeping the same functionality are covered under thisinvention. All such generalizations are covered by this invention.

It will be appreciated that the various apparatus and methods describedin this summary section, as well as elsewhere in this application, canbe expressed as a large number of different combinations andsubcombinations. All such useful, novel, and inventive combinations andsubcombinations are contemplated herein, it being recognized that theexplicit expression of each of these combinations is unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Schematic graphic of a process according to one embodiment ofthe present invention.

FIG. 2: Plot of hydrogen percentage verses SR temperature as produced ina method according to one embodiment of the present invention.

FIG. 3: Log plot of H2 vs steam/CH4 mass ratio as produced in a methodaccording to one embodiment of the present invention.

FIG. 4: Power consumption in recycle mode as produced in a methodaccording to one embodiment of the present invention.

FIG. 5: Effect of recycle mode on H2/CO ratio as produced in a methodaccording to one embodiment of the present invention.

FIG. 6: Predictions of H2/CO ratio as produced in a method according toone embodiment of the present invention.

FIG. 7: FT liquids produced with a catalyst on finned tube as producedin a method according to one embodiment of the present invention.

FIG. 8: FT liquid carbon number distribution produced by our catalyst onfinned tubes at two pressures: Red squares at 250 PSIG and blue diamondsat 125 psig as produced in a method according to one embodiment of thepresent invention.

FIG. 9: H2 production from biogas and then from biogas & digestate asproduced in a method according to one embodiment of the presentinvention.

FIG. 10: Peak H2 production at near feed capacity as produced in amethod according to one embodiment of the present invention.

FIG. 11: Main SR reactor power demands as produced in a method accordingto one embodiment of the present invention.

FIG. 12A is a cross sectional view of a rotary steam and carbon dioxidereformer as used in some embodiments of the present invention.

FIG. 12B is a portion of the cross sectional view of FIG. 8A.

FIG. 12C is a portion of the cross sectional view of FIG. 8A.

FIG. 13: Placement of stream/CO2 duplex rotary reformer into a processaccording to one embodiment of the present invention, and also thesystem 100 of FIG. 1.

FIG. 14: Schematic representation of a portion of a process according toone embodiment of the present invention.

FIG. 15: Process schematic showing how a waste stream can be made torelease energy without having to burn the waste or the syngas accordingto one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated device, and such further applicationsof the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates. At least one embodiment of the present inventionwill be described and shown, and this application may show and/ordescribe other embodiments of the present invention, and further permitsthe reasonable and logical inference of still other embodiments as wouldbe understood by persons of ordinary skill in the art.

It is understood that any reference to “the invention” is a reference toan embodiment of a family of inventions, with no single embodimentincluding an apparatus, process, or composition that should be includedin all embodiments, unless otherwise stated. Further, although there maybe discussion with regards to “advantages” provided by some embodimentsof the present invention, it is understood that yet other embodimentsmay not include those same advantages, or may include yet differentadvantages. Any advantages described herein are not to be construed aslimiting to any of the claims. The usage of words indicating preference,such as “various embodiments” or “preferably,” refers to features andaspects that are present in at least one embodiment, but which areoptional for some embodiments, it therefore being understood that use ofthe word “preferably” implies the term “optional.”

The use of an N-series prefix for an element number (NXX.XX) refers toan element that is the same as the non-prefixed element (XX.XX), exceptas shown and described. As an example, an element 1020.1 would be thesame as element 20.1, except for those different features of element1020.1 shown and described. Further, common elements and common featuresof related elements may be drawn in the same manner in differentfigures, and/or use the same symbology in different figures. As such, itis not necessary to describe the features of 1020.1 and 20.1 that arethe same, since these common features are apparent to a person ofordinary skill in the related field of technology. Further, it isunderstood that the features 1020.1 and 20.1 may be backward compatible,such that a feature (NXX.XX) may include features compatible with othervarious embodiments (MXX.XX), as would be understood by those ofordinary skill in the art. This description convention also applies tothe use of prime (′), double prime (″), and triple prime (′″) suffixedelement numbers. Therefore, it is not necessary to describe the featuresof 20.1, 20.1′, 20.1″, and 20.1′″ that are the same, since these commonfeatures are apparent to persons of ordinary skill in the related fieldof technology.

Although various specific quantities (spatial dimensions, temperatures,pressures, times, force, resistance, current, voltage, concentrations,wavelengths, frequencies, heat transfer coefficients, dimensionlessparameters, etc.) may be stated herein, such specific quantities arepresented as examples only, and further, unless otherwise explicitlynoted, are approximate values, and should be considered as if the word“about” prefaced each quantity. Further, with discussion pertaining to aspecific composition of matter, that description is by example only, anddoes not limit the applicability of other species of that composition,nor does it limit the applicability of other compositions unrelated tothe cited composition.

What will be shown and described herein, along with various embodimentsof the present invention, is discussion of one or more tests orsimulations that were performed. It is understood that such examples areby way of example only, and are not to be construed as being limitationson any embodiment of the present invention. Further, it is understoodthat embodiments of the present invention are not necessarily limited toor described by the mathematical analysis presented herein.

Various references may be made to one or more processes, algorithms,operational methods, or logic, accompanied by a diagram showing suchorganized in a particular sequence. It is understood that the order ofsuch a sequence is by example only, and is not intended to be limitingon any embodiment of the invention.

What will be shown and described herein are one or more functionalrelationships among variables. Specific nomenclature for the variablesmay be provided, although some relationships may include variables thatwill be recognized by persons of ordinary skill in the art for theirmeaning. For example, “t” could be representative of temperature ortime, as would be readily apparent by their usage. However, it isfurther recognized that such functional relationships can be expressedin a variety of equivalents using standard techniques of mathematicalanalysis (for instance, the relationship F=ma is equivalent to therelationship F/a=m). Further, in those embodiments in which functionalrelationships are implemented in an algorithm or computer software, itis understood that an algorithm-implemented variable can correspond to avariable shown herein, with this correspondence including a scalingfactor, control system gain, noise filter, or the like.

This application incorporates by reference U.S. patent application Ser.No. 14/847,798, filed Sep. 8, 2015, titled PROCESS AND SYSTEM FOR DUPLEXROTARY REFORMER, incorporated with regards to operation, components, andother aspects of the reformer shown in FIGS. 12A, 12B, and 12C.

In FIG. 1, there is shown one embodiment of an improved duplex kilnsystem 1000 that combines the functions of the conventional kiln,steam/CO₂ reformer, and the high temperature filter into a single unit.In FIG. 1, is shown how the new concept of a duplex kiln can be followedby a desulfurizer/getter bed, quench heat exchanger for providedsuperheated steam for the duplex kiln, and the Brayton turbine forgenerating power by cooling the syngas, which is then fed to both aFischer-Tropsch reactor and Shift/Pressure Swing Absorption System.

FIG. 2 shows the effect of temperature. In FIG. 3 is shown the effect ofsteam/CH₄ ratio. FIGS. 4 and 5 shows the effects of recycle. FIG. 6shows the comparison with published effects of steam/CH₄ ratio. FIGS. 7and 8 shows the advantage of using a Fischer-Tropsch process of twounits that make the high-carbon product, make steam and accomplishessequestration carbon balance in capturing nearly all of the carbondioxide emissions. In FIG. 8 it is shown how the Fischer-Tropsch processthat makes paraffin wax product for carbon sequestration accomplishesrecycling the light hydrocarbons consisting of methane, ethane,ethylene, propane, etc. to avoid their emissions as powerful greenhousegases (i.e. methane) and also recycling the lighter hydrocarbons to helpmaintain a higher H₂/CO ratio of the syngas. It also describes how awaste stream can be made to release energy without having to burn thewaste or the syngas. At the same time the waste can be converted intouse carbon-containing fertilizer, hydrogen fuel, and acarbon-sequestering, high-carbon content product of commercial value,such as unsaturated, high-density paraffin wax.

FIG. 6 shows the use of a conventional indirectly fired, calcining kilnwhere the very hot syngas exiting from the steam reformer can heatcarbon dioxide gas or air to supply the indirect heat to the kiln totake over from the natural gas burners commonly used. Or this heat fromheat exchanger 114, can be used to heat the recycle gas stream 116.These two methods of heat integration can be used in combination aswell.

The purpose of the following experimental work was to determine variousways in which to react the CH₄ and CO₂ to get useful syngas, andpreferably avoid the release of the CH₄ and CO₂ to the atmosphere.

One operational aspect of the operation and maintenance cost of the fullsize unit is the steam/CO₂ reformer (SR) operating temperature used toobtain a high quality syngas at the proper H₂/CO ratio in the range of1,200-1,400° F. FIG. 2 shows the temperature results to date reachingthe 27% H₂ goal. Experimental data herein show that H₂/CO=2.11±0.5 wasmeasured.

One economic benefit is obtained from operating at the lowest steam/CO₂reformer temperature and the lowest superheated steam addition toachieve the required FT H₂/CO ratio. An analysis using the mass ratio ofsteam to methane is shown as a log plot is shown in FIG. 3.

One useful steam and CH₄ mixture appears to be a ratio of about 1.1. Thecurved lines at the upper left show the results of different temperatureD2W simulations involving Gibbs Free Energy Minimization. They all showthe temperature effect and show clear maxima at each temperature. Thestrongest temperature increase appears to at 1.1 Steam/CH₄ mass ratio.Thus, a slight 10% excess of steam is indicted as optimal. Blue datasymbols points are pilot data.

The percentage CH₄ conversion comparing theoretical equilibriumcomposition to experimental non-catalytic conversion achieved in ourSteam/CO₂ reactor design is about 48%. This arises from equilibrium isthe maximum ideal conversion without any kinetic limitations.

One possible conclusion is that recycle mode had a negligible effect onthe H₂ production, as shown in the D2W simulation results shown in FIG.10 and the two data points using recycle of FIG. 7 at H₂ levels of21-24% and Steam/CH₄ ratio around 1.4. They are in line with othernon-recycle mode data points. The H₂ production of 0.135 lb. moles/hr.is about the same as the flow configuration without use of a blower. Oneaspect of the recycle mode is to produce pressure stability and makeoperation easier and simpler for automatic control. A possible advantageof recycle mode is that it consumes a small increase in power, as shownin FIG. 4.

The effect of steam/CH₄ ratio and temperature is confirmed bypredictions as shown in FIG. 6. This data shows why it is useful inoperating the main steam/CO₂ reactor at high temperature such as over1500° F. (813° C.) to obtain the CH₄ conversion over 92%.

The analytical laboratory work was done on two samples, the first wasrun at 250 psig and second at 125 psig.

The analysis included the extraction of the chromatogram for the 10xdilution run to get a better sense of the statement below about thefingerprint. The (likely) C8 peak is just before the 2.88 min retentiontime peak (C9), and is appropriately positioned with an expectedrelative retention time (looks like C8). The other stuff is unknown,since this technique (GC-FID) does not have ability to explore massdetection, but it could be a mix of other light organics with lowerresponses by FID (i.e. PAHs), or maybe olefins.

FIG. 7: Shows the GC/FID Chromatogram for the FT Liquids produced by ourcatalyst on finned tubes at two pressures. The sharp narrow peaks arethe laboratory standards and the lower and wider peaks are the resultsfor our FT liquids. The variety of peaks at the left of C8, are lightercompounds discussed above.

FIG. 8: shows the FT liquid Carbon number distribution produced by thecatalyst on finned tubes at two pressures: 125 psig as blue diamonds and250 psig at red squares. The results are graphically displayed as a logscale. As can be seen, the pressure has an effect in shifting thefractions of naphthas, kerosenes, diesel, and wax fractions. For smallsize FT process skids, it is possible that better economics are realizedat the lower pressures.

Referring to FIG. 12, the functionality of the embodiment of FIG. 12 iscombined into a single kiln to increase the thermal efficiency andreduce the cost. This design is referred to as the Duplex Kiln, 1, thatin some embodiments combines the functions of the conventional kiln,steam/CO₂ reformer, swirl fines drop out, the high temperature filter,recover of high temperature radial heat loss, heating internal heatingof helical spiral flights at the wall into a single unit.

Referring to the duplex kiln 1 in FIG. 12, the waste stream 6 is fedoxygen-free through the large entry pipe 14 combined with recycle lightgases through pipe 12. This entry region remains stationary whereas thekiln tube wall, 4, rotates as shown by arrow 22 and is sealed by meansof a pair of bellows tensioned rotary plates, 10, where in the bellowsapplies pressure to the pair of rotating sealing plates, 52A at the leftand 52B at the left which rotates with the tube 4 powered by drivepinion gear 20. Note that the bellows 10 is at the cold end of theduplex reformer where this bellows will have longer life. The thermalexpansion is about 5″ typically and the bellows can accommodate thismovement, as well as the wide pinion drive gears. At the hot end of theduplex reformer the drive pinion is in a V-shaped gear arrangement tohandle the end thrust from thermal expansion. As the waste enters tube14, the gaseous portion moves above the waste into the kiln as gasstream 16. Once inside the kiln rotating tube 4, the solids are droppedinto the bottom of kiln by chute 18. The waste solids 6 drop by thischute 18 onto the moving helical spiral flights 26 moving from left toright and carrying with them the waste 24. These helical spiral flights26 are hollow with the gas flowing, 30, in their interior from right toleft, counter-current to the waste and leaving through gas exit tube 8.

Again referring to FIG. 12, as the waste 24 is moved progressively tothe right by the helical spiral flights 24 if eventually enters a flatwall region 38 where there is a tumbling media 42 that helps break lumpsof waste and helps form an aggregate material that leaves the rotarykiln through chute 54.

Further referring to FIG. 12, the gases 16 enter the swirl region 36where their flow trajectory is driven into a curved flow by vanes 34. Inthis region 36 the curved flow trajectory velocity throws the particlesdownward as shown by arrow 32. For their these gases with less finespass through porous media filter 40 and enter the electrical heatedreactor 48 that has interior disk and donut baffles 46 which steer theflow to pass cross flow around the cylindrical heating elements 50 forconvective heat transfer. This reactor 48 does not rotate as it is fixedto the stationary region of the kiln by fixes cylindrical structure 58that is attached to the cylindrical, insulated cap 52 The hole patternallows the finished syngas 30 to enter the helical spiral flights 26 andleave this duplex kiln at exit pipe 8. This electrically heated reactor48 is further supported mechanically by hollow truss 56 through whichsuperheated steam and optionally added CO₂ if fed by port 60 and entersthis reactor through port 44. This added reactant gases help furtherdrive the formation of the finished syngas for substantial conversion tothermodynamically equilibrium with an internal residence time attemperature of around 1.5 seconds.

In FIG. 13 the duplex rotary steam/CO₂ reformer 1 is shown in anembodiment of the waste-to-fuel and energy process design. This showsthe concept of the rotary reformer with an integral steam reformer atthe exit end which eliminates some high temperature piping and the heatlosses associated with such piping. The biomass/waste feedstock 4 entersthe process around room temperature at the left. The finished syngas 30produced leaves at the left at somewhat above room temperature. Thesolid biomass/waste enters at the left and is mixed together with warmlight end gases 12 from the downstream process units, such as gas 108from Fischer-Tropsch and/or PSA offgases 122 from the hydrogenpurification section shown as process steps 126 and 132.

Now referring to the exit end to the right of the duplex rotarysteam/CO₂ reformer 1, the electrically heated, hot gas-phase mainsteam/CO₂ reformer 50 is inserted though the right side. Any inorganicsand solid carbon phases leave the duplex rotary reformer warm throughexit pipe 54 that is configured to eliminate any entry of outside air.Besides the electrical heating, there are optionally two other means ofsupplying the endothermic heat needed to drive the steam/CO₂ reformingchemistry: [1] warm recycled light end gases 12 as well as hot powergeneration hot gases 80 from Brayton cycle heat engine and 93 from hotcathode nitrogen-rich off-gases. This hot gas heat enters the reformer 1into the typical oven that surrounds commercial kiln retort tubes thatrotate, and these gases do not enter with the recycled gases 12 thatenter the process flow which is preferably oxygen-free. Hot fuel cellanode off-gases 95 containing unreacted H₂ and CO plus CO₂ and lighthydrocarbons are mixed into 60 to enter the electrically heatedsteam/CO₂ reformer.

Referring to FIG. 13, the finished syngas 30 from the duplex rotaryreformer, 1 is next heated by heat exchanger 114 using waste heat 116from the duplex reformer 1, so that the hot syngas 112 enters theabsorber clean-up beds 117 for sulfur, mercury, chlorine, etc. removal.The cleaned, finished syngas 118 is now ready for use in productproduction of fuels, hydrogen and power. This clean syngas 120 firstenters the Shift Converter 132, then enriched with H₂ in steam 130enters the PSA 126 for concentrating the hydrogen. Offgases 122 from theShift Converter are recycled back 12 to the front end of the duplexreformer. The PSA produces renewable hydrogen fuel, 124. There is alsoan optional steam stream 128 that can be used in stream 60 to assist theelectrically-heated reformer 50.

Additionally in FIG. 13, this syngas 188 can be sent via 110 down to theFischer-Tropsch (FT) where it enters via 96 into the FT reactor 98 thatproduces the crude paraffinic hydrogen fuel 106. This FT reactor 98 ishighly exothermic and produces large quantities of high pressure steamthat can be used in the Brayton cycle turbine/engine 85 to makeelectrical power 82 via generator 83. The hot turbine off gases 80 canbe used to heat the duplex reformer. The crude FT paraffinic fuel 106 isseparated and distilled in unit 100 into a naphthenic fuel, like, JET,104 and into FT Diesel No. 2 103, both of which can be sold. Theoff-spec streams 102 consisting mostly of wax and alcohols and steam canbe used in stream 60 for further reforming in the electrically heatedsteam/CO₂ reformer 50 to make more syngas and eventually more product.

In FIG. 13, the clean syngas remaining 94 enters a solid oxide fuel cell92 that converts electrochemically this syngas into electricity andpower 88 to drive the plant and also start up the plant when the fuelcell is run on natural gas or tank propane or diesel. This fuel cell 92anodically reacts some 85% of the syngas and the 15% left over gasconsisting of unreacted H₂ and CO plus CO₂ can be used in stream 60. Thecathode off-gas consists of hot nitrogen and this can be used to furtherheat the duplex reformer via stream 93.

Some embodiments of the present invention provide thermal efficiencyderived from inside of the rotary reformer (commercial calcinerequipment) with the inserted spiral flights that are hollow and allowthe hot syngas to be counter-flowed from the right back out the entrythrough the rotary plate seal. This provides the heat for the solidsfeed and cools the syngas as well. In the center is a cyclonic swirlvane section that helps drop out fine solids entrained in the gas. Thefines drop into the inorganic solids left after initial steam reformingaround 900-1100° F. The cleaned syngas passes through a mesh filter andenter the high temperature main steam/CO₂ reformer that is electricallyheated. The hot syngas at 1800-2000° F. that exits is rich in hydrogen,as shown in Table 1. This hot finished syngas is then passed through thespiral flights in counterflow direction to exit cooled at the entry portof the rotary reformer. This is generally about 15 wt % of the feedstockentering the process. Carbon efficiency is achieved via the bottom exitthere is also the option of a rebar section that tumbles to break up anylarger pieces of solids into an aggregate size the material that can beused as a 70-80% carbon rich 0-10-10 slow release pellet fertilizer,thus sequestering this carbon in the ground and not resulting therelease of GHG to the Earth's atmosphere.

Next a number of examples are given according to various embodiments ofthe present invention:

EXAMPLE #1

Using the empirical formula for typical municipal solid waste, MSW, weshow two reactions: first the conventional steam reforming using astoichiometric amount of steam to make just CO and H₂.

MSW and Stoichiometric SteamC₁H_(1.67)O_(0.47)+0.53 H₂O→CO+1.36 H₂In this case 1 kg of waste will yield 1.45 kg of syngas.

EXAMPLE #2 Superstoichiometric in CO₂ and C₂H₄

By contrast, here is one improved reforming reaction which involves asubstoichiometric amount of steam but has the light hydrocarbonFischer-Tropsch and shift/PSA overhead represented for simplicity byC₂H₄, plus CO₂ and H₂, added.C₁H_(1.67)O_(0.47)+0.55 C₂H₄+0.69 H₂+1.5 CO₂+0.04 H₂O→3.68 CO+2.67H₂  [1]

In this case, 1 kg of waste will yield 5.11 kg of syngas, which is a350% increase in the mass of syngas product formed from a given mass ofwaste.

This achieves the formation only of CO and H₂, and thus isstoichiometric which respect to the combination of steam plus CO₂ plusC₂H₄. Thus, less steam (i.e sub-stoichiometric) is required andgreenhouse-problematic light hydrocarbons and CO₂ can be used in largeamounts to achieve overall the stoichiometric conversion to syngasdesired with a preferred H₂/CO ratio around 0.73. The products CH₄, C₃H₈or other light hydrocarbons are actually involved in the real world incombination with C₂H₄ shown in the reaction. In a typicalFischer-Tropsch process all of these light hydrocarbons are formed andwould be in the recycle. Thus, the use of Fischer-Tropsch is simplifiedin some embodiments. The CH₄ is produced as a part of the waste lightgases coming off the tops of the Fischer-Tropsch gravity separator.Preferably, no distillation is required. Any other light gases that arealso carried along with the waste CH₄ can go back to the steam reformeras well.

In some embodiments it is economic to recycle 100% of the CO₂ andwhatever optimum amount of CH₄ from Fischer-Tropsch to make the wholesystem balance, sequestering all of the CO₂ while making useful paraffinwax that is high in carbon content, high in commercial value, and notburned in its lifecycle. So in FIG. 13 the Improved Carbon Sequestrationcan be accomplished as shown by the carbon balance. Thus, by adjustingthe carbon in the Shift/PSA recycle 86 plus the carbon in theFischer-Tropsch overhead recycle 108, the carbon in the waste 100 ismade to just equal the carbon in the Fischer-Tropsch product, paraffinwax 102. So what could be accomplished in some embodiments is thesequestration of the carbon in the waste by the formation of the highcarbon content paraffin wax. Yet other embodiments of the presentinvention contemplate other Fischer-Tropsch-like processes that can beselected that will accomplish this total carbon sequestration.Commercially, there maybe be an economic optimum situation where one maynot want to sequester all of the carbon in the waste, but this exampleshows that this is possible.

Alternatively, the reactor in FIG. 13 can consist of a conventionalshell and tube heat exchanger with the pellets of catalyst in the tubesand the liquid phase in the shell. To avoid temperature hot spots in thetubes, the ratio of catalyst diameter to tube diameter shall preferablybe more than about one to five.

FIG. 14 shows in yet another embodiment how simplified theFischer-Tropsch process can become in this new steam/CO₂ reformingprocess of waste conversion with recycle streams. Referring to FIG. 14,the cleaned and warm syngas 154 from the kiln 104 shown in FIG. 13 ispassed into an air cooler 300 where it is temperature-controlled toabout 180° C. (350° F.) at the exit of the air cooler 301. This stream301 is then fed to the compressor 302 where the pressure is increasedfrom around one atmosphere (15 psig) to 3.5 MPa (468 psig) at its outlet303 which feeds the Fischer-Tropsch reactor 305 containing aFischer-Tropsch catalyst 304 within its vertical tubes. This reactorcarries out the synthesis reactions making a range of hydrocarbons fromCH₄, light hydrocarbons up to heavy hydrocarbon paraffins whilereleasing heat.

The reaction below shows how the syngas produced in reaction [1] abovecan be used to make high carbon-content products such as high density,unsaturated paraffin wax as a means of sequestering carbon in a productthat has significant commercial value. The other compounds formed can berecycled back into reaction [1] so that they are not released to theenvironment. Also there are some CO₂, H₂ and H₂O that can be recycled aswell from the shift converters and PSA units. Again, C₂H₄ is being usedto represent the large range of light hydrocarbon gases for simplicityof discussion.3.68 CO+2.67 H₂→0.055 C₂₀H₃₀+0.55 C₂H₄+1.47 CO₂+0.734 H₂O  [2]

The temperature, pressure, H₂/CO ratio of the syngas, and the residencetime together control the molecular range of the Fischer-Tropschproducts 316 that is then fed into the separator 318. The mixture ofhydrocarbons gravimetrically separates here into three fractions: water320, paraffins 322 and light gases overhead 222. In some embodimentsthere is a simple process, not requiring complex distillation,crystallization, or boiling. And it is this interfacing with thesteam/CO₂ reforming kiln and the fuel cell that makes such asimplification possible and novel.

Yet other embodiments of the present invention include the use of otherFischer-Tropsch reactor concepts different from the conventionalcatalyst—packed, multi-tube (i.e. shell and tube) exothermic butisothermal reactor. Such a reactor can consist of a spiral heatexchanger where the catalyst is placed in the spiral annular regions.Such a design is shown in FIG. 15 that shows the spiral heat exchangeFischer-Tropsch Reactor wherein the syngas feed 303 (or 86 in FIG. 13 or154 in FIG. 14) enters into the spiral annuli 512 that are packed withsupported catalyst. The converted syngas consisting of the light gasestogether with some un-converted syngas that leaves from nozzle 222.These annuli are immersed in water between the spirals with its levelcontrolled just above the end of the annuli. The exothermic heat boilsthe water to make steam that is used to feed a steam/turbo generator.The boiler feedwater enters via a nozzle. At the bottom of the reactorthe liquid paraffin wax forms within and drains out the exit after itleaves the nozzle. Paraffin wax recycle from the separator 318 (shown inFIG. C), enters the outer spiral annulus through a nozzle. In oneembodiment, there is a square array of fin tubes are surrounded by asquare baffle so the syngas enters into a side nozzle and flows downunder the bottom of the baffle and up the inside thru all the fins andexits thru nozzle at the vessel top. FT liquid forming on the catalystsurface drains down to bottom of fin tubes, drips into bottom pool, andexits thru bottom nozzle. In still further embodiments, all of thesurfaces of the fins having a catalyst on the surface are contiguous.This arrangement of catalysts on the fin surfaces has provided asurprising advantage, which is the ease in lighting off the reactionprocess.

Finally, FIG. 15 describes how a waste stream can be made to releaseenergy without having to burn the waste or the syngas. At the same timethe waste can be converted into use carbon-containing fertilizer,hydrogen fuel, and a carbon-sequestering, high-carbon content product ofimportant commercial value, such as unsaturated, high-density paraffinwax.

Referring to FIG. 15, the waste stream enters the process as stream 100into rotary kiln 104 where it is steam/CO₂ reformed via the chemistry inreaction [1] above to form a high-hydrogen content syngas stream 154where its high temperature heat is used in boiler 416 to produce steam418, as well as a high carbon content product steam 112 that containsglass and metal as well as a nitrogen-free, high Potassium-Phosphorous(PK) fertilizer solid particulate of commercial value. The reaction inkiln 104 uses light gases, CO₂, and steam recycled as 402 fromdownstream process units consisting of shift converter 458,pressure-swing absorber 456, Fischer-Tropsch reactor 452 and itsparaffin product separator 454. This recycle stream 402 comes from thecombined streams 400 made up of 222 and 306 plus stream 414 made up ofstreams 410 and 412. The syngas 154 produced in kiln 104 is split intotwo streams 303 and 404, with 303 feeding the Fischer-Tropsch units 452and 454 producing paraffin product 322 and stream 404 feeding the Shift458 and PSA 456 that produce hydrogen product 408 and optional CO₂ at409. In addition, the Fischer-Tropsch unit 452 is exothermic andproduces steam 420 that can be used to drive a steam turbine to makeelectricity to run the plant and be exported for sale. Water streams 316and 320 are used to makeup boiler feedwater. One result of this linkageand interface of the three process blocks of steam-reforming of waste tothe Shift/PSA and the Fischer-Tropsch is to convert the waste tohydrogen fuel and into high-carbon PK fertilizer and carbon-sequesteringparaffin with a release of heat. And this is done preferably withoutburning the waste and without releasing the huge amounts of greenhousegases typical of a combustion process. Various embodiments of thepresent invention pertain to various apparatus and methods of destroyingwaste and producing steam, heat and useful products in the carbonlesseconomy of the future.

FIG. 15 shows the use of a conventional indirectly-fired, calcining kiln1 where the hot syngas exiting from the steam/CO₂ reformer, 50 can heatrecycle carbon dioxide gas or air in stream 93 to supply the indirectheat to the kiln to take over from the natural gas burners commonlyused. Now referring to FIG. 15, the above kiln 1 is shown interfaced tothe shift/PSA unit 98 or 452 using its exhaust recycle 306 and theFischer-Tropsch process 454 recycling the methane and light hydrocarbongases via 222 back to the steam/CO₂ reforming kiln. These streamsinvolving the waste 100, the shift/PSA unit exhaust recycle 236 and theFischer-Tropsch overhead stream 222 are combined with the proper amountof steam 4 to carry out the steam/CO₂ reforming inside the kiln 104. Orthis heat from heat exchanger 114, can be used to heat the recycle gasstream. These two methods of heat integration can be used in combinationas well.

This reaction equilibrium favors the H₂ and CO at temperatures around orabove 700° C. (1300° F.) so that when the syngas moves from theconventional calcining kiln 1 in FIG. 13 into the steam/CO₂ reformer 50,which involves temperatures around 1050° C. (1900° F.), so that thisreaction is almost 100% completed. Following this reactor 50, stream 112passes into heat exchanger 114 whereas option #1 in an inert gas, suchas CO₂ produced elsewhere in the process, or outside air is heated bythe very hot syngas in steam to be fed via stream into a series ofmultiple indirect burners 93 of the conventional kiln. These burners,conventionally used for natural gas, would be replaced with an injectionjet that would supply the hot gas directly into the oven-furnace area ofthe conventional kiln. Or as option #2 this heat from heat exchanger206, can be used to heat the recycle gas stream 236. These two methodsof heat integration can be used in combination as well. The rest of theprocess in some embodiments is substantially the same as in FIG. 13.

EXAMPLE #3 CO₂ Enriched Syngas

A further improvement in the reforming reaction which involves asubstoichiometric amount of steam but has the light hydrocarbonFischer-Tropsch and shift/PSA overhead represented for simplicity byC₂H₄, plus CO₂ and H₂, added.C₁H_(1.67)O_(0.47)+0.2567 C₂H₄+0.2 CO₂+1.434 H₂O→1.123 CO+0.591CO₂+3.029 H₂

In this case, the reformation reaction is allowed to form CO₂ in thesyngas, such that the stoichiometric ratio of (H₂—CO₂)/(CO+CO₂)=1.42which is favorable for the Fischer-Tropsch reaction as follows:1.123CO+0.591CO₂+3.029H₂→0.0428C₂₀H₃₀+0.257C₂H₄+0.344CO₂+1.617 H₂O

This achieves an increase in the amount of paraffin formed andgreenhouse-problematic light hydrocarbons and CO₂ are entirely recycledback into the reformer, with a small portion of the water condensed asproduct water. Thus, the use of Fischer-Tropsch is further simplified.As before, the CH₄ is produced as the major part of the waste lightgases coming off the tops of the Fischer-Tropsch gravity separator. Nodistillation is required. Any other light gases that are also carriedalong with the waste CH₄ can go back to the steam reformer as well. Insome embodiments there are no CO₂ emissions since the CO₂ formation inthe Fischer-Tropsch is recycled back into the reformer.

In FIG. 13 what has been achieved in this case is the substantial orcomplete elimination (i.e. stream 216 is zero) of the Shift/PSA processstep at a capital savings. Likewise, in FIG. 15, stream 409 is zero.Some embodiments of the present invention accomplish near-total or totalsequestration of the carbon in the waste by the formation of the highcarbon content paraffin wax. Yet other embodiments contemplate otherFischer-Tropsch products that can be selected that will accomplishcarbon sequestration. Commercially, there maybe be an economic optimumsituation where one may not want to sequester all of the carbon in thewaste, but this example shows that this is theoretically possible.

EXAMPLE #4 Process Flowsheet Mass Balance with Fischer-Tropsch

The process flowsheet layout based on FIG. 15, but with the processdetails, was completed and the mass balance done where the flow split ofsending syngas to Shift/PSA system and to Fischer-Tropsch was varied.The chemistry within the steam reformer was given in reaction [1] aboveand in the Fischer-Tropsch unit in reaction [2] above. The results havebeen summarized in Table 2 below, showing how the products of thewaste-to-energy plant, such as hydrogen, water carbon dioxide andparaffin was can be varied depending on the needs of the customer andthe marketplace. The process choices can set the products that are madein some embodiments. The case shown is for wet waste with 15% water anda scale of 4 tonnes/day.

TABLE 2 Shift Fischer H₂ Net PSA Tropsch H₂ Kg/ Water CO₂ ParaffinElectricity % % Recycle day Kg/day Kg/day Kg/day kWe 62 38 Low 490 −15476587 859 185 62 38 Hi 395 −922 5823 1093 235 50 50 Hi 254 0 4096 1441310 38 62 Hi 232 229 4416 1526 328 19 81 Hi 46 1475 2888 1984 426 0 100Low 0 2264 1928 2290 492 0 100 Hi 0 3842 0 2875 618 0 100 OptCO₂ 0 15940 3851 861

As the process option is shifted more toward Fischer-Tropsch, moreparaffin, water, and electricity products are made and less hydrogenfuel produced. With the various Fischer-Tropsch, no hydrogen and nocarbon dioxide are produced and the amount of water, paraffins, andelectricity are maximized. The electricity is a net number, after theinternal electricity consumption within the plant is removed and used.The last line in Table 2 covers the case presented in Example #3,showing a great increase in Fischer-Tropsch product as well aselectricity generated. Our experimental work has confirmed the mechanismdiscussed above from the actual measured production of FT wax, FT waterand FT hydrocarbon product.

EXAMPLE #5 Process Flowsheet Heat & Mass Balance for Increased Hydrogen

The process flowsheet layouts are given in FIGS. 13, and 14 showing therecycle stream going back to the rotary kiln. This example covers thecase when the off-gases from the hydrogen purification and CO₂extraction steps are the recycle stream going back to the kiln.

The detailed heat and mass balance for this flowsheet for maximizinghydrogen production using a cellulose feed was done by a commercialprocess simulator. The purpose of this optimization was to maximize thehydrogen production, minimize the need for electric grid power tooperate the plant, and produce dry ice (liquid carbonic) product. Thefeedstock in this example is the dimer of cellulose, called cellubiose.This dimer portion of the large cellulose chain is replicated some25,000 to 250,000 times.

The biomass enters the rotary kiln steam reformer as a solid and/orliquid phase together with the recycle gases. Within the kiln thismixture is heated, volatiles are vaporized, solids are chemically brokenand decomposed, and the mixture is further heated as it moves from leftto right through the kiln. At the end of the kiln, solids are removed.These solids are about 15% (by mass) of the biomass feed. With anagricultural or forest biomass feedstock, this solid product stream is avaluable freely-flowing, gravel-like, slow-release form of PKfertilizer. The gases generated inside the kiln react with the waterthat enters with the biomass and with any additional water that comeswith the recycle stream. The steam/carbon dioxide reforming chemicalreaction is endothermic (it requires supplying energy) and occurs as thekey step in the process generating a syngas stream consisting ofhydrogen, carbon monoxide, carbon dioxide, water and other light gases,such as methane, ethane, ethylene, etc.

The hot syngas leaving the rotary kiln is heated, mixed with hotsuperheated steam, and enters the vertical steam reformer where it isfurther heated to complete the steam/carbon dioxide reforming reactionproducing the highest concentration of hydrogen with the least amount ofother organic contaminants, such as higher hydrocarbons and aromatics.

Various embodiments expressed herein address biomass phase-change as asolid-to-vapor chemical decomposition. The biomass is decomposed into avapor by breaking the chemical bonds. This process is not the classicalsolid-to-liquid transition (heat of melting), or the liquid-to-vaportransition (heat of vaporization). As these molecular fragments movethrough the kiln, the temperature increases, causing furtherdecomposition by the hydroxyl radical attacking and breaking the nextstronger bond, such as carbon-carbon bonds. The last and toughest bondsto be attacked are the aromatic carbon-carbon bonds. This decompositionresults in the aromatic ring coming apart which creates other organicgases such as ethane, ethylene and butyne. Small amounts of these gasescan recombine to form other very stable aromatic compounds.

This very hot syngas leaving the steam reformer passes through heatexchangers to recover energy to supply heat to processing equipment orto generate steam for process use and/or power generation. The coolhydrogen-rich syngas is passed to the hydrogen purification section,shown in the on the right-hand portion of the graphic in FIG. 13, wherethe carbon monoxide is reacted with more superheated steam to formcarbon dioxide and additional hydrogen as well as release of heat. Thisrich hydrogen gas mixture is purified in a commercial pressure swingadsorption unit yielding a hydrogen stream ranging from 99.9% to 99.99%purity. The remaining carbon dioxide and other light gases pass overheadinto the carbon dioxide recovery system. Here a clean carbon dioxidestream is produced that feeds a commercial carbon dioxide liquefactionplant where either liquid carbon dioxide (liquid carbonic) or dry ice isproduced. The remaining light gases are recycled to the kiln.

Surprisingly, it was found possible to recover enough heat from theexothermic shift converter to preheat the recycle gas and add enoughheat to the material feeding the kiln to change its phase to a vapor andheat it to 400 to 500° C. Leaving the exit of the kiln is thefreely-flowing granular residue, 15% of the biomass on a dry basis,which is formed in the rotary kiln. This residue is high in carboncontent. In this way, the heat added to the commercial kiln is suppliedby recovered process heat and trimmed with electric heat to control thereaction temperature at 400° to 500° C.

The simulation modeled the commercial steam reformer. It mixed theproduct from the rotary kiln at 1 atmosphere with superheated steamadded at 300 PSIA and 267° C. Waste heat from the syngas heats the steamreformer feed to around 875° C. The steam reformer was modeled as anisothermal reactor. The heat added to the commercial steam reformer issupplied by recovered process heat and trimmed with electric heat tocontrol the reaction temperature at around 875° C.

The simulation modeled a commercial heat exchanger cooling the steamreformer hot syngas effluent while recovering energy to be returned tothe process. Next, water is condensed out of the syngas and removed in acommercial vapor liquid separator. The vapor leaving this separatorflows to a commercial carbon bed adsorber, where small amounts ofaromatic organic compounds are removed. The vapor leaving this bed flowsto a 3-stage compressor that increases the process pressure to 300 PSIAfor the downstream shift converter and pressure swing adsorption (PSA)H₂ recovery. A heat exchanger module removes the heat of compressioncooling the vapor to 260° C. In practice, the compressor uses first andsecond stage intercoolers and the 3-stage after-cooler.

The syngas from the compressor is mixed with superheated steam and thecombined flow enters the carbon monoxide shift converter. The shiftconverter is modeled as an adiabatic reactor. This reactor convertswater and carbon monoxide to desired carbon dioxide and hydrogenproducts. Energy is recovered in a heat exchanger. This energy isreturned back to the process. The water that condenses is removed in avapor-liquid separator. The vapor from this separator flows to apressure swing adsorption unit where 80% of the hydrogen leaving the PSAis recovered as product with 99.9% purity. The remaining vapor leavingthe PSA unit flows to the carbon dioxide recovery system, modeled as asimple separation device. In practice this equipment could be a membranesystem or an amine system with a liquid carbonic and/or dry iceproduction unit. The vapor leaving CO₂ separator flows to the heatexchanger, preheating the vapor prior to feeding the rotary kiln.

One aspect of this process configuration with the major recycle loopcarrying the unconverted hydrogen and other light gases from the PSAunit, is that these gases are further converted in the steam/CO₂reforming units to make more hydrogen product, as used in the massbalance preferring that the hydrogen coming in with the feedstock mustleave the process as the hydrogen product. Additional or higherconversion stages in the PSA unit are not needed when this recycle loopis used.

To validate the process simulation predictions, a biomass sample ofgrape pomace, available in huge quantity from the wine industry, wastest-run in a pilot unit as illustrated in FIG. 13, less the hydrogenpurification and liquid carbonic steps, to produce the syngas stream.This measured syngas stream was compared with the Design-2 processsimulation prediction below in Table 4.

TABLE 4 Comparison of Pomace Produced Syngas With Simulation ResultsComponent Test Results Simulation Prediction Hydrogen 59.4% 61.4%Oxygen + Argon*   0% Nitrogen*   0% Carbon Monoxide 32.4% 31.3% CarbonDioxide 2.96% 6.2% Methane  5.1% Ethane, acetylene, ethylene 570 ppm<940 ppm Propane** 98 ppm Butanes** 60 ppm Benzene** 198.4 ppm 1 ppb C7and above** 380 ppm Hydrogen Sulfide** 59.8 ppm Carbonyl Sulfide** 1.74ppm Methyl Mercaptan** 16.6 ppm Carbon Disulfide** 35.3 ppm *Air leakageaccounted for. **In practice, these components will be removed by a zincbed, carbon bed or are recycled to the kiln

The comparison of the test results and the simulation prediction ofsyngas is excellent. The kiln and steam/CO₂ reformer chemical reactors'process temperatures and steam content, in the simulation, match thoseof the pilot demonstration.

EXAMPLE #6 Digestate and Biogas

A combined dairy digestate solids and digester biogas run according toanother embodiment of the present invention was performed. First, therun was started with Biogas only (10 cc/min CH₄ and 20 cc/min CO₂—so 66%CO₂ as the Biogas leaving the commercial digesters. As can be seen bythe increasing the blue curve in FIG. 9, the H₂ increased from zero andto 5% in 6 minutes with the steady state plateau in 15 minutes, at whichpoint the digestate was fed slowly at first, reaching a plateau of 17%at the right side of FIG. 9.

Then, as can be seen in FIG. 10, as the digestate feedrate was increasedto capacity, the H₂ rose from 17% in the center of the figure to 30% atthe right of the figure. The sharp dip was the period for sampling thissyngas for the GC analysis to capture the first of the high plateau. TheGC showed a 27% H₂ level, in close agreement with the H₂ sensor. The H₂level went on to reach 30% thereafter. And oxygen level (the orangeline) remained low and near zero throughout. The H₂/CO ratio from thisrun was 2.11±0.5.

The main SR reactor power demand at this H₂ plateau was 58% or 4.76 kWe,as shown in FIG. 11 as the red curve. The evenly-spaced 2 minute pulsesin power are a result of the PID control system feeding power to thevarious heaters. These will eventually be smoothed out as each of theirPID loops are tuned for more even control. With 8/10 run completion, thefeed was stopped and, as can be seen in FIG. 11, the main SR reactorpower demand dropped over 15 min. to 42% that is the normal idle powerdemand with no chemistry going on.

Also of interest in FIG. 11 is the orange curve at the left shown anincreasing set of power pulses reaching 50% in the rotary reformer finalsection running at 1000° F. This shows that a rich clump of digestatereached the final rotary reformer section demanding increased heat forprocessing before going on the main SR reactor. As the feed became moreuniform the orange curve was steady.

Various aspects of different embodiments of the present invention areexpressed in paragraphs X1, X2, and X3 as follows:

X1. One aspect of the present invention pertains to a process thatprovides the interface between a steam/CO₂ reforming waste conversionsystem using organics generating syngas without a catalyst and aexothermic organic hydrocarbon synthesis reactor operating at 125 psigthat recycles the light tail gases hydrocarbons off of this synthesisreactor.

X2. Another aspect of the present invention pertains to a process thatprovides the interface between a steam/CO₂ reforming waste conversionsystem using liquid, gas, and solid organics generating syngas and anexothermic organic hydrocarbon synthesis reactor that recycleshydrocarbons off of this synthesis reactor, and reacts them in thesteam/CO₂ reformer operated below 1800° F., also recycling thehydrocarbons to control and help maintain a H₂/CO ratio from 1.5 to 3.2of the syngas as might be desired for the synthesis reactor.

X3. Yet another aspect of the present invention pertains to a method ofreforming of organic waste material. The method preferably includesproducing a first stream of synthesized hydrocarbon gas includinghydrogen and carbon monoxide. The method preferably includes mixingorganic waste with a first portion of the hydrogen and carbon monoxidefrom the first stream. The method preferably includes reforming themixture of the first stream and the waste with steam and carbon dioxideand producing a second stream of synthesized hydrocarbon gas and heat.The method preferably includes using a second portion from the secondstream for said producing a first stream.

Yet other embodiments pertain to any of the previous statements X1, X2,or X3, which are combined with one or more of the following otheraspects. It is also understood that any of the aforementioned Xparagraphs include listings of individual features that can be combinedwith individual features of other X paragraphs.

Where a exothermic organic hydrocarbon synthesis reactor combined with aparallel shift converter/pressure-swing absorption unit to accomplishthe conversion of the syngas to commercially-marketable hydrogen fuel,ample steam to generate electrical power for the plant and for export,and a high-carbon content liquid organic product that sequesterssubstantially the carbon in the waste stream—all without any burning ofthe waste or the syngas.

Where the light gases from the exothermic organic hydrocarbon synthesisreactor that is a Fischer-Tropsch unit are recycled back to the steamreformer for destruction and avoiding release to the environment.

Where carbon dioxide and a portion of the hydrogen from the Shift andPressure Swing Absorber units are recycled back to the steam reformer toadjust the H₂/CO ratio for optimum utilization in the Fischer-Tropschunit.

Where small impurities in the syngas that could damage the sensitivecatalysts in a high temperature fuel cell do not damage the more robustcatalysts (i.e. iron or cobalt-based) in a Fischer-Tropsch unit.

Where the best clean-up of syngas impurities involves a process wherethere are both a high temperature filtration step and a sulfur-,chlorine-, and nitrogen-containing compound removal step as well as achilling and condensation step downstream which includes a HEPA filterand a guard bed to protect high temperature fuel cell electrochemicalcatalysts.

Where the best clean-up of syngas impurities involves a process wherethere are both a high temperature filtration step and a sulfur-,chlorine-, and nitrogen-containing compound removal step as well as achilling and condensation step downstream which includes a HEPA filterand a guard bed to protect Fischer-Tropsch catalysts.

Where a exothermic organic hydrocarbon synthesis reactor that is greatlysimplified because its many tail or overhead streams can be used asrecycle to the steam/CO₂ reforming process.

Where a power recovery system that involve the combined use of a shiftand PSA unit as well as the Fischer-Tropsch unit to make best use ofrecycle streams and waste heat.

Where an exothermic reactor consists of a Fischer-Tropsch reactor.

Where an exothermic reactor consists of a methanol synthesis reactor.

Where an exothermic reactor consists of a methanation reactor.

Where heat to the kiln sections doing endothermic steam/CO₂ reforming issupplied by recycling the syngas through the holoflite screw to heat thewaste and do reforming.

Where a recycle loop carrying the unconverted hydrogen and other lightgases from the PSA unit back to the feed-end kiln, wherein these gasesare further converted in the steam/CO₂ reforming units to make morehydrogen product, as required in the mass balance dictating that thehydrogen coming in with the feedstock must leave the process as thehydrogen product; so that in this way, additional or higher conversionstages in the PSA unit are not needed when this recycle loop is used.

Which further comprises controlling said producing a first stream tomaintain a ratio of hydrogen to carbon monoxide from about one and onehalf to about three and two tenths.

Wherein said reforming does not include burning the waste or the portionof the first stream.

Wherein said reforming is without the use of a catalyst.

Which further comprises using the heat from said reforming to drive aheat engine and generator to produce electricity.

Wherein said producing a first stream is with a Fischer-Tropschreaction.

Wherein said reforming is at a temperature from about one thousand fivehundred degrees F. to about one thousand eight hundred degrees F.

Wherein said using a second portion includes cooling the second portionprior to said producing a first stream.

Wherein said using a second portion includes pressurizing the secondportion prior to said producing a first stream.

While the inventions have been illustrated and described in detail inthe drawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly certain embodiments have been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

The invention claimed is:
 1. A method of reforming of organic wastematerial, comprising: producing a first stream of synthesizedhydrocarbon gas including hydrogen and carbon monoxide; providing to awaste reforming conversion system a supply of organic waste; mixing theorganic waste with a first portion of the hydrogen and carbon monoxidefrom the first stream; reforming the mixture of the first stream and thewaste with steam and carbon dioxide and producing a second stream ofsynthesized hydrocarbon gas and heat; and using a second portion fromthe second stream for said producing a first stream.
 2. The method ofclaim 1 which further comprises controlling said producing a firststream to maintain a ratio of hydrogen to carbon monoxide from about oneand one half to about three and two tenths.
 3. The method of claim 1wherein said reforming does not include burning the waste or the portionof the first stream.
 4. The method of claim 1 wherein said reforming iswithout the use of a catalyst.
 5. The method of claim 1 which furthercomprises using the heat from said reforming to drive a heat engine andgenerator to produce electricity.
 6. The method of claim 1 wherein saidproducing a first stream is with a Fischer-Tropsch reaction.
 7. Themethod of claim 1 wherein said reforming is at a temperature from aboutone thousand five hundred degrees F. to about one thousand eight hundreddegrees F.
 8. The method of claim 1 wherein said using a second portionincludes cooling the second portion prior to said producing a firststream.
 9. The method of claim 1 wherein said using a second portionincludes pressurizing the second portion prior to said producing a firststream.